Contour forming machine, including tracer control mechanism



y 4, 1954 P. J. CAMPBELL 2,677,310

CQNTOUR FORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec.15, 1948 17 Sheets-Sheet l IN VEN TOR. Pa 01 'I 6072: 0 92? y 1954 P. J.CAMPBELL 2,677,310

CONTOUR FORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec.13. 1948 17 Sheets-Sheet 2 GROUND STR/P INVENTOR.

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CONTOUR FORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec15, 1948 17 Sheets-Sheet 4 IN VEN TOR.

['a a Z J. (a/290 5377 y 1954 P. J. CAMPBELL 2,677,310

CONTOUR FORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec.15. 1948 17 Sheets-Sheet s IN VEN TOR.

P n I J. ('(r av Jo e22 May 4, 1954 P. J. CAMPBELL CONTOUR FORMINGMACHINE, INCLUDING TRACER CONTROL MECHANISM Filed D90. 13, 1948 17Sheets-Sheet 6 IN VEN TOR.

Pa 2! i .lfawzyofieli BY May 4, 1954 P. J. CAMPBELL CONTOUR FORMINGMACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec. 13, 1948 17Sheets-Sheet '7 MUM INVENTOR.

PauZ 6217101061922 May 4, 1954 P. J. CAMPBELL 2,677,310

INCLUDING TRACER CONTROL MECHANISM CONTOUR FORMING MACHINE,

l7 Sheets-Sheet 8 ANN Qmm um INVENTOR.

1'7 Sheets-Sheet 9 May 4, 1954 P. J. CAMPBELL CONTOUR FORMING MACHINE,mcwnmc; TRACER CONTROL MECHANISM Filed Dec. 13, 1948 y 4, 1954 P. J.CAMPBELL 2,677,310

CONTOUR FORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM y 1954 P. J.CAMPBELL 2,677

CONTOUR FORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec.1a, 1948 1'7 Sheets-Sheet 11 3835 12 I INVENTOR.

Pa. 21? J. [aW2 5 eZZ May 4, 1954 P. J. CAMPBELL 2,677,310

CONTOUR FORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec.15, 1948 17 Sheets-Sheet 12 IN VEN TOR.

Pa a2 J Ca 212 0 6 all Zwm May 4, 1954 P. J. CAMPBELL CONTOUR FORMINGMACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec. 15, 1948 17Sheets-Sheet 1a NN EN y 1954 P. J. CAMPBELL 2,677,310

CONTOUR FORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec.15, 1948 17 Sheets-Shee 14 INVEN TOR.

Paul J: flaan qfieii eff/i0 r22 a y 1954 P. J. CAMPBELL 2,677,310

INCLUDING TRACER CONTROL MECHANISM CONTOUR FORMING MACHINE,

Filed D90. 15, 1948 17 Sheets-Sheet 15 Nmum INVENTOR. PaazZll'aivzloiil'lz BY y 1954 P. J. CAMPBELL 2,

CONTOUR FORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM Filed Dec.13, 1948 17 Sheets-Sheet 16 INVENTOR.

PauZ Jfla anpZeZZ 220 race May 4, 1954 P. J. CAMPBELL CONTOUR FORMINGMACHINE, INCLUDING TRACER CONTROL MECHANISM l7 Sheets-Sheet 17 FiledDec. 13. 1948 AMC II We y a h e 0 R a w j W W m w w w W m a 9 a J m u mw MIT. M 2 MM I Patented May 4, 1954 UNITED STATES PATENT OFFICE CONTOURFORMING MACHINE, INCLUDING TRACER CONTROL MECHANISM The inventionrelates to a machine or appara tus for shaping or cutting a workpiece toprovide it with one or more contours corresponding to the contour orcontours of a pattern or template. Within the scope of the invention,the character of the pattern or template may be widely varied and it mayhave a contour or contours in only one plane or may have contours indifferent planes. The pattern may consist of one or more lines on adrawing. Also within the scope of the invention, the character of theworkpiece may be widely varied and it may be a drawing with one or morecontour lines produced thereon and corresponding to the contour orcontours of the pattern or template.

As illustrated in the drawings and as hereinafter described, there arethree separate machines each embodying the invention which machines areadapted for effecting successive operations in the making and inspectingof master blades for axial flow turbines and the like. The first machineis adapted for making a threedimensional template having contourscorresponding to some of the contours of the master blade to be made. Inthis machine the pattern comprises lines on a drawing corresponding incontours to the required contours on the template and the templateconstitutes the workpiece. The second machine is adapted for the cuttingor contouring of a master blade with contours corresponding to those ofthe template. In this last said machine the template made by the firstmachine constitutes the pattern or tern plate and the master bladeconstitutes the workpiece. 'The third machine is adapted for forminglines on a drawing corresponding to selected contours of the completedmaster blade made by the second machine, the said drawing serving forinspection purposes to determine the accuracy of the said contours ofthe master blade. In this last said machine the completed master bladeconstitutes the template and the drawing with the lines formed thereonconstitutes the Workpiece. While the invention is exemplified by thesaid three machines, it is not so limited and it may be embodied inmachines intended and adapted for other uses.

One object of the invention is to provide a machine having a tracer forfollowing the contour or contours of the pattern and for controlling thecutting or shaping piece in accordance with the said pattern contour orcontours and having an electrically responsive control means for thetracer which enables it to closely follow the contour or contours of thepattern without contacting the said pattern.

Another object of the invention is to provide more broadly anelectrically responsive tracer control means for use with a pattern andhaving the characteristics above set forth.

A further object of the invention is to provide an apparatus as lastabove outlined, wherein the electrically conductive template is or maybe an electrically conductive line on a drawing.

A further object of the invention is to provide a machine and method formaking an article such as a template for subsequent use in the making ofmaster blades for axial flow turbines and compressors. The said bladetemplate conforms at various positions to the contours of lines on apreviously prepared drawing or drawings which lines represent crosssectional contours of the required master blades at selected spanwisespaced stations or positions. In ac cordance with this phase of theinvention, the line or lines on the drawing or drawings are preferablyelectrically conductive and constitute an electrically conductiveinitial template which guides or controls the tool that forms therequired contour or contours on the blade template.

A further object of the invention is to provide a machine having atemplate with different contours in spaced parallel planes and adaptedto cut a workpiece with various contours some of which correspond to thesaid template contours and others of which correspond to contoursinterpolated between the said template contours.

Still another object of the invention is to provide a machine having atemplate with different contours in spaced parallel planes and alsoadapted to out the contours on the workpiece in a relationship diiierentfrom the relationship of the contours of the template.

Other objects of the invention will be apparent from the drawings andfrom the following description.

Referring to the drawings:

Figure 1 is a front elevational view of a pantograph constructed inaccordance with the teaching of the invention. Certain portions of theframe to the right and left and of the table to the right have beenbroken off in order to facilitate its illustration in the drawing.

Figure 2 is a top view on a smaller scale of the table and associatedparts shown in Figure 1.

Figure 3 is a cross-sectional view along the line 33 of Figure 2.

Figures 4 and 5 are front and side views respectively, of thetracer-head of Figure 3.

Figure 6 is a view along the lines 5-6 of Figure 1. I

mechanism Figure 7 is a view along the line .'-1 of Figure 6.

Figure 8 is a side View, partly in section of the template arbor, thetemplate cutter and ciated mechanism of Figure l on an enlarged scale.

Figure 9 is a top view of the template, taken along the lines 99 ofFigure 8.

Figure 1-1) is a diagrammatic view of the electrical circuit of theservo-mechanisrn and sensing or tracing means of Figures 1 to 9.

Figure 11 is top view of the table and sens g means or follower ofFigures 1 to 9 with a moo fied drawing thereon showing how a twis "darticle such as a turbine blade may be untwisted with the pantograph ofFigures 1 to 9 to form an untwisted template.

Figure 12 is a top view of an untwisted tom-- plate made according tothe teaching of igure 11.

Figure 13 is a top view'of a contouring machine for forming complete orfinished ar cle from a partial template such as shown in r ures 1 to 9.In the form shown, the machine of Figure 13 also has a retwisting deviceor th reon for forming complete or finished twisted ar icles, such asturbine blades, from untwisted templates such wn in Figure 12.

Figure 14 is an end View of the machine in Figure 13.

Figure 15 is a view along the line l5-li Fi ure 13.

Figure 16 is a view along the line of lti=3 of Figure 13.

Figure 17 is a front view of the magnetic clut .h for the tool feedingmechanism shown in Figures 13 and 16.

Figure 18 is a View along the lines i3-i8 of Figure 17.

Figure 19 is a sectional view of the tool or milling cutter of Figures13 and 16.

Figure 20 is a View along the line 28.2il of Figure 19.

Figure 21 is a sectional view through a portion of the retwisting deviceor mechanism of Figure 13.

Figure 22 is a view along the line 22--22 of Figure 21.

Figure 23 is a top view of the differential which is operated by theretwisting mechani Figure 24 is a view along the line il -s Figure 23.

Figure 25 is diagrammatic View 2 e trical circuit for the contouringdevice and retwisting mec lllliSlTl of Figures to show n spark currentfor the circuit and spark gap illustrated in Figure 25.

Figure 26 is schematic view of a modified forzn of a flexure shaping orcontouring means.

Figure 27 is a front view of the bendin of Figure 26.

Figure 28 is a plan view of the inspection pantograph.

Figure 29 is a front view, partly in the pantograph of Figure 28.

Figure 3G is a view, partly broken away, along the lines 39-39 of Figure29.

Figure 31 is a front view of the recording pen of Figure 28.

While the method and apparatus of this in vention is not limited to themaking of any particular article, the presently preferred embodiment ofthe invention shown in the accomdevice section, of

General description, The template making machine, The contouring machineand The inspection machine.

General description I'ereoiore in the making of blades for axial. wturbines and compressors it has been more or less conventional practicefirst to determine the preferred airfoil contour or cross-sectional ofthe blade, or the profile of a blade einent, at each oi a plurality ofstations spaced spanwise or lengthwise of the blade. Large scaledrawings are then made of such calculated or computed blade elements andfrom the drawings a master craftsman or pattern maker carves, largely byhand, master blade which h .s the profile shown by the drawing at eachof ne "elected stations and which is faired or conoanwise, again by handand eye, beween said computed blade elements to form a radually curved,smoothly surfaced complete master blade. Foe master blade so formed maythen be used a pattern, die or model from v hich working blades, or theactual blades with which the turbine or compressor is constructed. maybe cast, forged or machined. Because the master blade mustbe made withextreme accuracy to very close tolerances and because it is usually madeof steel or a hard metal for accuracy, smooth surface finish anddurability, the work. of nialrig such model must be done by a skilledcraftsman at a high cost per master blade. This is pa ticularly truewhere the blade is of the usual type having a progressively varyingblade angle from root to tip (twisted, like an aircraft propeller) whichconsiderably complicates the worlr of fairing or contouring the surfacesbetween the computed profiles. Furthermore, this hand process is a verytime consuming one, which becomes factor of great importance when aturbo-jet or similar engine with an axial flow compressor is being made,because s .ch engines ordinarily require large number of rows of and acorrespondingly high number or" aster blades.

According to the prs-ent invention the first step in making a masterblade may be the in the prior art method described above, i. thecross-sectional blade profiles are calculated or computed at a pluralityof selected spanwisc spaced stations t en are drawn, usually upon anenlarged scale 5 n 2i.-:l. Such a drawing, made in the usual manner uponlarge square thin fiat steel sheet, is shown 560 in Figures 1 and 2. Itcomprises a series of closed curves I02, H24, 233, and 98 representingthe projections upon the plane of the drawing of the computed profilesof four selected blade elements. A greater or less number o computedblade elements, and drawing curves, may be used as described. The planeof the drawing in this instance is taken as a plane normal to a panwiseaxis of the blade (this axis is represented in the drawing by the pointI IQ) which is a radius or straight line intersecting the axis ofrotation of the compressor or turbine at right angles thereto andpassing through the center of

